Grease gun



M. o...EN`Gsr-:TH

Aug. 24, 1954 GREASE GUN 2 Sheets-Sheet l Filed April 19, 1950 Il",illu".

A TTO Aug. 24, 1954 M, o. ENGSETH GREASE GUN 2 sheets-sheer 2 FiledApril 19. 195o INVEN TOR MARTIN O. ENGSETH Patented Aug. 24, 1954UNITED' STATES PATENT OFFICE GREASE GUN Martin 0. Engseth, Wayzata,Minn. Application April 19, 1950, Serial No. 156,830 4 Claims. (Cl.10S-153) My invention relates to grease guns and has for an object toprovide a grease gun by means of which exceedingly high pressure can beprocured.

Another object of the inventionresides in providing a grease gun havinga piston controlled by a lever and operable upon manipulation of saidlever a second time to increase the pressure obtainable by the firstmanipulation of the lever.

A still further object of the invention resides in providing a springfor procuring' movement of the piston and in further providing a catchfor engagement with a shoulder formed on a part movable with said pistonto cock the piston against the action of said spring and releasing saidpart upon its arrival at the end of its path of motion.

Another object of the invention resides in providing a second shoulderon said part adapted tobe engaged by said catch in the event that thepiston does reach the end of its stroke and by means of which the springmay be further compressed to increase the force on the spring and thepressure produced by said piston.

` Other objects of the invention reside in the novel combination andarrangement of parts and in the details of construction hereinafterillustrated and/or described.

In the drawings has been illustrated a grease gun provided with a bodyhaving a cylinder and with a discharge passageway leading to a suitablefitting. The said cylinder communicates intermediate its ends with areceptacle for grease detachably mounted thereon. In alignment with thecylinder is a bore in which a plunger connected to the pistonandactuated by a spring in said' bore operates to force said piston alongsaid cylinder and to discharge the lubricant therein outwardly throughsaid discharge passageway.`

This plunger is formed with two longitudinally spaced shoulders adaptedto be` engaged by a catch formed on the end of a reciprocating link. Thesaidz link is pivoted to a lever which in turn is pivoted to said bodyand which when operated serves to bring said `catch into engagement withthe outermost shoulder and to' compressA the spring and movethe' pistonto the outermost end of said cylinder; A cam on said body engaging a camfollower on said link disengages the' catch from said shoulder and`releases the plunger to permit said spring to urge the piston' alongsaid cylinder; In the event that the joint to be lubricated is pluggedup and the lubricant does not completely flow out of the cylinder,another operation of thelever causes said catch to' engage the innershoulder and `to further compress the 2 spring to procure additionalforce to direct the lubricant into the joint to be lubricated.

In the drawings:

Fig. 1 is a longitudinal elevational sectional View of a grease gunillustrating an embodiment of the invention and showing the piston ineX- tended position.

Fig. 2 is a view similar to Fig. 1 of a portion of the structure showntherein and illustrating the arrangement of the piston when the same hasbeen partially retracted and with the catch in engagement with anotherof the shoulders of the plunger.

Fig. 3 is a view similar to Fig. 2 showing the piston in fully retractedposition and with the catch in engagement with the same shoulder asshown in Fig. 2.

Fig. 4 is an elevational cross sectional view taken substantiallythrough the discharge nipple on line 4 4 of Fig. 1.

The invention disclosed comprises a body l0 in which the operating partsof the device are disposed. This body is constructed as a casting whichis formed with an angular portion 20 exv tending outwardly therefrom. Inthis angular portion is a cylinder l2 in which is slidably mounted apiston I3. Thisn piston is of rather small dimensions so that as saidpiston is forced along the cylinder suitable pressure can be lprocuredwithin said cylinder. The body I0 has a tubular portion l1 which isformed with a bore I 8 extending angularly With reference to thecylinder l2 and communicating therewith. This bore has an enlargementl9` forming a valve seat 2l at the inner end of said' enlargement. Aball valve member 22 is disposed within this enlargement and is adaptedt"o` seat against the seat 2|. The outer end` of the bore I9 is formedwith threads 23 into which is screwed a nipple 24 having mounted on itsouter end'afltting 25. The fitting 25 is adapted to be connected to thepart to be lubricated and inasmuch as the said fitting forms noparticular feature of the invention, the same has not been shown indetail.

The angular portion 20` of the body I 0 has a tubular extension 26"which is formed with a bore 21 concentric with the cylinder l2 andcommunieating therewith. This bore forms a guide in which is slidablymounted' a plunger 2B and to 50' which thepiston It is attached. Thisplunger is formed with twogrooves 29'and 30 which provide shoulders 3`l`and 32 on the plunger. A compres-v sion coil spring 33' isdisposedwithin the bore 2T and engages at onev end thev outer endfof theplungerv 28'A and" at its" other end a disc 62 which serves as a springseat and rests on a retaining ring 34 received in a recess 35 in the endof the extension 26. By means of this construction the piston I3 isurged to travel along the cylinder I2 to force the lubricant enteringsaid cylinder into the bore I8 and to discharge the same past the valvemember 22 and into the nipple 24.

Attached to the body I is a receptacle II for the lubricant vused withthe grease gun. The receptacle I I consists of a tube 36 having acylindrical chamber 31 extending throughout the length thereof. One endof this tube is screwed into a threaded boss 38 formed as a part of thebody I0. This boss has a passageway 39 therein which communicates withthe cylinder I2 intermediate the length thereof and with the cylindricalchamber 31 in tube 36. The outer end of the tube 36 is flared inwardlyas` indicated at 49 to form a closure for theouter end of the tube.Slidably mounted within the chamber 31 is a piston 4I of any suitableconstruction and which is attached to a piston rod 42. The

said rod extends through the closure 48 being l slidably guided in acircular opening 43 in said closure and has attached to its outer end ahandle 44 by means of which the piston may be manipulated. A compressioncoil spring 45 disposed within the chamber 31 bears against the piston4I and against the closure 49 and tends to urge the piston for movementtoward the body I9 of the grease gun and to force the lubricant withinthe chamber 31 ahead of the piston 4I through passageway 39 and into thecylinder I2. A

The receptacle II may be lled with lubricant by removing the tube 36from the boss 38 and inserting the open end of the tube 36 into thelubricant. Upon then drawing the piston 4I inwardly into the cylinderand against the action of the spring 45 the chamber 81 ahead of thepiston may be filled with lubricant. To temporarily hold the charge oflubricant within the cylinder a shoulder 46 is formed on the piston rod42 and which is adapted to engage a shoulder 4l formed on the closure40. When the piston rod is moved laterally the tube 36 with its chargeof lubricant is then screwed back into the boss 33 and upondisengagement of the shoulder 49 from the shoulder 41 the grease gun isready to be used.

For operating the plunger 28 a retracting mechanism I4 is employed whichconsists of a lever 48 preferably constructed of sheet metal and whichhas two arms 49 and 50 formed with flanges 66 straddling the body I9 ofthe gun as best shown in Figs. 1 and 4. he entire lever is formed bystamping the parts from sheet metal and bending the same into a U-shapedform. A rivet 5I extends through the body I0 and also through theflanges 66 of arms 49 and serves to pivot the lever 48 for swingingmovement from a position shown in Fig. 1 to that shown in Fig. 3. Thearms 49 and 50 are arranged in angular relation and at the part 65thereof at the vertex be- Ytween the said arms is provided a rivet 52which extends completely through the flanges 65. This rivet pivotallysupports an actuator 53 and through which the rivet 52 extends. The saidactuator has a catch 54 at the free end of the same which is adapted toenter a slot 55 in the wall of the extension 26 and to be receivedwithin either of the grooves 29 or 30 and to engage either or" theshoulders 3| or 32. The actuator 53 is urged toward the plunger 28 bymeans of a torsion spring 56, one end 51 of which engages the said 4.catch and the other end 58 of which engages the arm 48.

For releasing the piston I3 a cam 59 is employed which is mounted on theextension 26 of the body I0. This cam is adapted to engage a camfollower 6I) on the end of the actuator 53. When the said catch reachesthe cam 59 said cam engages the follower 60 and forcibly withdraws thecatch 54 from engagement with the shoulders 3I or 32 and releases theplunger 28 and piston I3.

The method of using the invention is as follows: The chamber 31 is nrstfilled with lubricant as previously described and the tube 36 screwedback into the boss 38. For the sake of clearness the lubricant has notbeen shown in the drawings. Upon moving the piston rod 42 into aconcentric position with reference to the opening 43, the piston 4I isfree to travel toward the body I8. Since the passageway 39 is normallyfilled with air, the piston 4I moves slightly and the shoulder 46 ismoved inwardly and away from the shoulder 41.

32. If now pressure is applied to the lever 48.

the same is moved toward the position shown in Fig. 3. When the cam 59is engaged by the cam follower 60 the catch 54 is withdrawn from thegroove 38 and out of engagement with the shoulder 32 and the plunger 28released. In such position the end of the piston I3 is below the opening39 and piston 4I forces lubricant into the portion of the bore I2 aheadof said piston. Upon release of the plunger 28 spring 33 forces thepiston I3 along the cylinder I2 discharging the lubricant in the samethrough the bore I8, past the ball 22 and into the nipple 24 from whichthe lubricant is directed to the part to be lubricated. Due to the sizeof the cylinder I2 and piston I3 considerable pressure is exerted whichis usually sumcient to force lubrication into a cavity in which formerlubrication has hardened. However, when the resistance to the entry oflubricant into such cavity is exceedingly great the piston I3 becomesstalled and does not move throughout its entire stroke. In such case theplunger 28 would be in the position shown in Fig. 2. The catch 54 mightthen enter the groove 29 and engage the shoulder 3|. Pressure on thelever 48 would then cause the plunger 28 to be further retracted and thespring I5 to be additionally compressed. Such compression of the springI5 would cause the spring to exert a greater force on the piston I3 andto give the same additional drive for forcing the lubricant into thecavity. It will readily be comprehended that with this invention theplunger may be retracted in steps. With such an arrangement less forceis required in compressing the spring and retractingl the plunger whenthe passageway to the cavity to be lubricated is free.` Whenconsiderable resistance is encountered in discharging the lubricant, asecond operation of the device further compresses the spring and therequired additional force is procured. Thus, the user only has to exertthe additional effort required in retracting the piston when thepassageway leading to the cavity is not open. Upon subsequent retractionof the piston I3 ball 22 seats against seat`2I and compels the drawingof lubricant from the chamber 31 through passageway 39 and into bore I2.

acercar The advantages of the invention are manifest. The device issimple and easy to operate and does not require any degree of skill oringenuity. If the lubricant is not delivered on the iirst application,the movement of the lever is repeated and the device automaticallyincreases the pressure. The entire device can be constructed at anominal expense and is simple in construction. lThe parts are soarranged that the grease gun is con-- venient to hold and manipulate andis adapted to be applied in close quarters.

Changes in the specific form of the invention, as herein described, maybe made within the scope of what is claimed without departing from thespirit of the invention.

Having described the invention, what is claimed as new and desired to beprotected by Letters Patent is:

l. In a grease gun, a body providing a cylinder for the reception ofgrease, a piston slidable in said cylinder, a guide in said body, aplunger connected to said piston and movable along said guide, a springseat carried by said body a spring acting between said plunger and saidspring seat and urging said plunger and piston in a direction tocompress the grease in said cylinder, said plunger upon movement in theopposite direction retracting said piston in said cylinder,longitudinally spaced shoulders formed on said plunger and disposedtransversely of the direction of movement of said plunger, a leverpivotally connected to said body and having a part movable substantiallyin the same direction as said plunger, an actuator movably connected tosaid lever at the denoted part thereof, a catch on said actuator, saidactuator being spring biased to bring said catch into engagement witheither of said shoulders, said lever when moved in one direction causingsaid actuator to move said plunger in a direction to retract saidpiston, and stressing said rst named spring to a greater degree when thecatch is in engagement with one shoulder than with the other and releasemeans carried by said body and engaging said catch, for moving saidcatch laterally away from said plunger and out of engagement with theshoulder with which it cooperates when the actuator reaches a certainposition in its piston retracting movement.

2. In a grease gun, a body providing a cylinder for the reception ofgrease, a piston slidable in said cylinder, a guide in said body, aplunger connected to said piston and movable along said guide, a springseat carried by said body a spring acting between said plunger and saidspring seat and urging said plunger and piston in a direction tocompress the grease in said cylinder, said plunger upon movement in theopposite direction retracting said piston in said cylinder,longitudinally spaced shoulders formed on said plunger and, disposedtransversely of the direction of movement of said plunger, a leverpivotally connected to said body and having a part movable substantiallyin the same direction as said plunger, an actuator movably connected tosaid lever at the denoted part thereof, a catch on said actuator, saidactuator being spring biased to bring said catch into engagement witheither of said shoulders, said lever when moved in one direction causingsaid actuator to move said plunger in a direction to retract saidpiston, and stressing said rst named spring to a greater degree when thecatch is in engagement with one shoulder than with the other and releasemeans including a cam and a cam follower in relative sliding en- 6,gagement with one another, one thereof being disposed on said actuatorand the other on said body, and movable relative to one another in thedirection of movement of said actuator said cam having a. surfaceoblique to the direction of travel of the actuator and causing lateralmovement of the catch relative to the plunger and disengagement of thecatch from the shoulder engaged thereby when the actuator reaches acertain position` in its piston` retracting movement.

3'. Ina grease gun, a body` providing a cylinder for the reception ofgrease', a piston slidable in said cylinder, a guidein said. bodyVextending in the same direction as said cylinder, a plunger connectionto said piston and movable along said guide, a spring seat carried bysaid body a spring acting between said plunger and said spring seat andurging said plunger and piston in a direction to compress the grease insaid cylinder, said plunger upon movement in the opposite directionretracting said piston in said cylinder, longitudinally spaced shouldersformed on said plunger disposed transversely of the direction .ofmovement oifsaid plunger, a lever pivotally connected to said body andhaving a part movable substantially in the same direction as saidplunger, an actuator pivoted to said lever at the denoted part thereof,a catch on said actuator adapted to engage either of said shoulders, aspring acting be tween said actuator and said lever and urging saidcatch into engagement with either of said shoulders, said lever whenmoved in one direction causing said actuator to move said plunger in adirection to retract said piston and stressing said first named springto a greater degree when the catch is in engagement with one shoulderthan with the other and release means including a cam and a cam followerin relative sliding engagement with one another, one thereof beingdisposed on said actuator and the other on said body, and movablerelative to one another in the direction of movement of said actuatorsaid cam having a surface oblique to the direction of travel of theactuator and causing lateral movement of the catch relative to theplunger and disengagement of the catch from the shoulder engaged therebywhen the actuator reaches a certain position in its piston retractingmovement.

4. In a grease gun, a body providing a cylinder for the reception ofgrease, a piston slidable in said cylinder, a guide in said bodyextending in the same direction as said cylinder, a plunger connected tosaid piston and movable along said guide, a spring seat carried by saidbody a spring acting between said plunger and said spring seat andurging said plunger and piston in a direction to compress the grease insaid cylinder, said plunger upon movement in the opposite directionretracting said piston in said cylinder, longitudinally spaced shouldersformed on said plunger disposed transversely of the direction ofmovement of said plunger, a lever pivotally connected to said body andhaving a part movable substantially in the same direction as saidplunger, an actuator pivoted to said lever at the denoted part thereof,a catch on said actuator adapted to engage either of said shoulders, aspring acting between said actuator and said lever and urging said catchinto engagement with either of said shoulders, said lever when moved inone direction causing said actuator to move said plunger in a directionto retract said piston, and stressing said iirst named spring to agreater degree when the catch is in engagement with one shoulder thanwith the other and release means including a cam and a cam follower, inrelative sliding engagement with one another, one thereof being disposedon said actuator near said catch and the other being disposed on saidbody near the end of said guide most remote from the cylinder andmovable relative to one another in the direction of movement of saidactuator, said cam having a surface oblique to the direction of travelof the actuator and causing lateral movement of the catch relative tothe plunger and disengagement of the catch from the shoulder engagedthereby when the actuator reaches a certain position in yits pistonretracting movement.

References Cited in the le of lthis patent Number UNITED STATES PATENTSName Date De Fir Mar. 12, 1918 Tear Oct. 16,1934 Appleby Mar. 28, 1939Bijur Jan. 21,1941 Engseth Feb. 10, 1948

